Transmission control structure



DeC. l2, 1944. L Q BQYCE TAL 2,364,774

TRANSMISSION CONTROL STRUCTURE Filed April 15, 1941 INVENTOR LEONARD D,.B0YCEF IAN C. M? KECHNIE l ATTOLRJNIEY` Patented Dee. l2, 12944 2,354,774 TRANSMISSION CONTROL STRUCTURE Leonard D. Boyce, Mapl McKechnie, Detroit, assignor to Chrysler Park, Mich., said Boyce ewood, Mo., and Ian C.

Mich.: said McKechnie poration, St. Louis, Mo.,

Corporation, Highland a corporation of Delaware, and assigner to Carter Carburetor Cora corporation of Dela- Appueauon april 15, im, sex-au Nu. 383,631' s claims (ci. 'r4-412) This invention relates to transmission. control mechanism for automotive engines and consists particularly in a novel switch device arranged to be jointly controlled by the engine throttling mechanism and the suction in the engine intake manifold.

In automotive vehicles having variable ratio power transmission devices which operate automatically to reduce the ratio as the vehicle speed increases, it has been found desirable to provide means convenient of manipulation by the operator for reverting to a higher ratio (or lower speed gear ratio) when the operator is confronted with an emergency demanding fast acceleration. Such means have usually included an electro magnetic 'v actuator and a control circuit therefor including a switch which is arranged to co-act with the engine carburetor throttle control mechanism so as to cause a shifting to a lower speed gear ratio when the throttle valve operating mechanism is moved slightly beyond a full open throttle position. It has also been found, however, with auch arrangements,- that under certain conditions as where the vehicle is travelling at a comparatively high rate of speed, the transmission cannot be safely returned to a lower speed gear ratio, as above described, due to the consequent excessive engine speed.

It is, therefor, an object of the present invention to provide a manual control mechanism of the above character which includes means responsive to engine intake velocities for rendering the same inoperative above a predetermined engine speed. t

It is a further object of the present invention to provide a generally new and improved throttle actuated switch device which includes pressure responsive means for blocking its operation.

Other objects and advantages will appear upon referring to the following specification and ac companying drawing. Referring to the drawing Fig. 1 is a diagrammatic view showing a, portion of an automotive engine and including a carburetor and a power transmission unit with the present invention applied thereto.

Fig. 2 is a view of a portion of the carburetor shown in Fig. 1, taken on line 2-2, showing in section the switch device constructed in accordance with the present invention. v

Figs. 3 and 4 are dlil'erent operative views of the switch device shown in Fig. l.

Fig. 5 is sectional view oi the switch device taken on line S-l of Fig. 3.

Numeral i generally indicates an internal combustion engine having an intake manifold 2 on .which ignition devices (not which is mounted a carburetor, generally indicated at 2. The carburetor .is provided with a downwardly directed mixture conduit 4 and a mixture control valve la to which is attached a throttle operating lever I. Linkage for the remote control of thethrottle is indicated at l, l, l, l and Ill. A clutch and a set of manually shifted change speed transmission gears are mounted, respectively, in housings il rear portion of the enginef Rearwardly in a housing i3 is mounted a set of planetary transmission gearing so arranged that when the sun gear is locked against rotation the conventional changespeed transmission will be over-driven. A suitable arrangement of this type is shown in the patent to E. M. Claytor, #2,214,100 issued Septem ber 10, 1940. A solenoid actuator il mounted on the side of the overdrive housing i3, cooperates with locking mechanism (not shown) to lock the sun gear, and thus effect over-driving, when energized. Suitable means, as spring means, is employed to effect the release of said locking mechanism and permit the return to a lower speed ratio as selected in the conventional transmission when the solenoid circuitis broken.

Electrical energy for the Operation ot solenoid i5 is supplied by a storage battery I1 through a circuit I8 which comprises a governor switch generally indicated at I! and a throttle actuated switch generally indicated at 2l. The circuit may also include the usual key switch Isa through shown) are generally connected. Governor switch I9 may be oi' any suitable design and lsconnected to and driven by the yehicle drive shaft 2i or such part oi the vehicle having a rotative speed constantly proportional to the vehicle road wheels. The governor switch I! is calibrated to close the circuit at that point at a predetermined vehicle speed, say. in the order of 15 to 20 M. P. H.

Throttle actuated switch 20 comprises a two section housing structure, section 22 which may be formed as a metal casting and which, in the illustrated form, is cast integral with the carburetor main body member, and section 23 which, in

the precferred form the entire section is constructed as a casting of a dielectric material. It will be understood, however, that section 23 may be constructed as a metal casting with suitable necessary insulating inserts. Sections 22 and 22 are attached by any suitable means such as screws (not shown). Section 22 is provided with a horizontal bore 24 within which is slidably iitted ahollow plunger member 25. A coil spring 26 normally urges plunger 25 outward. A reach pin 21 and i2 secured to the received at one end in hollow plunger 25 is arranged to telescope therein and is normally urged toward an extended position by a coil spring 28.

Section 23 is also provided with a horizontal bore 29, of D shaped section (see Fig. concentric with the bore 24 in section 22. Fitted within bore 29 is a plunger member 30, of D shaped cross section constructed of dielectric material and a coil spring 3| arranged to urge plunger 30 toward the right. Plunger 30 is provided on its upper side with a, rectangular recess 32 which receives a switch blade 33. Switch blade 33 is normally urged upward against the upper straight wall of bore 29 by a pair of coil springs 34. Cast as inserts within section 23 are a pair of terminal posts 35 the lower ends of which are flush with the upper wall of bore 23. The upper ends of posts 34 extend substantially from section 23 and are adapted to receive conventional lead connectors. Switch blade 33 is provided with a pair of upwardly extruded bosses 35a which space the remainder of the switch blade from the upper wall of bore 29 and therefore the flush lower ends of posts `35. These bosses are so spaced as to come in contact simultaneously with the lower ends of posts 35 when plunger 30 is moved to its limit of travel to the right.

Switch housing section 22 is further provided with a vertical bore 36 communicating at its lower end with the atmosphere and at its upper end with the carburetor mixture conduit, at a point anterior to the mixture control valve, by means of passageways 31 and 31a. Slidably fitted within bore 36 is a. piston 38 which is normally urged downward by a coil spring 39. 'I'he lower end of piston 38 is provided with a cut-away skirt portion 38a having a slot 40 formed therein through which passes the outer end of reach pin 21. This arrangement prevents piston 3B from rotating. The piston 38 carries, attached thereto at its lower end, a blocking plate 4| having a perforation 42 therein of suiilcient size to-permit the passage therethrough of the reach pin 21. The upper end of the slot 40 contacting the reach pin 21 limits the downward travel of piston 38 and when the piston is in its downwardmost position the perforation 42 in blocking plate 4l is in line with the axis of reach pin 21 thus permitting its passage through the blocking plate.

The carburetor mixture control valve lever 5 is provided with an arm 43 which when the valve approaches a full open position contacts the outer end of plunger 25.

The operation of the device is as follows:

Operation of the vehicle above the predetermined speed at which it is desirable to have the overdrive gearing effective will cause the governor switch I3 to close the solenoid circuit at that point. 'Ihe circuit being normally closed at switch is thus complete effecting the actuation of the sun gear locking mechanism and causing the operation of the overdrive. If now, under these conditions, it is' desirable to drop back into a lower speed gear ratio to attain faster acceleration the throttle valve is moved to a full open position, as indicated in Fig. 3, causing throttle lever arm 43 to contact plunger 25 and to move the same and the reach pin 21 and switch blade plunger to the left to a circuit breaking position. The solenoid circuit is thus broken and the overdrive sun gear locking mechanism released rendering the overdrive ineffective. It will be understood that spring 28 in hollow plunger 25 is sufficiently stiier than spring 3ly to cause the shifting of plunger 30 when force is applied to plunger 25.

If, however, the engine is operating at a speed corresponding to a vehicle road speed of say 50 miles per hour or greater the velocity through the carburetor mixture conduit will result in a. pressure drop therein suiiicient to raise piston 3l upward against the resistance of spring 38 thus moving the blocking plate 4| upward and the perforation 42 therein out of alignment with reach pin 21. If, under these conditions, the throttle valve is moved toward a fully opened position the reach pin 21 will strike the blocking plate and continued movement of the throttle valve to a full open position will be permitted by the telescoping of reach pin 21 in hollow plunger 25. See Fig. 4.

The above description and accompanying drawing are intended to be illustrative and not limiting and the exclusive use of all modifications within the scope of the appended claims is contemplated.

We claim:

1. In combination, a prime 'mover having a uid induction conduit, a control valve in said conduit, a driven member, a variable ratio power transmission mechanism, a spring opposed electro-magnetic actuator capable of advancing the speed of the driven member with respect to the prime mover when energized, an energizing circuit for said actuator, means responsive to the speed of said driven member for closing said circuit, means movable with said control valve for breaking said circuit, and a pressure responsive device having a suction connection with said induction conduit at a point anterior to said control valve and being responsive to a predetermined suction therein to prevent the breaking of said circuit by said last-mentioned means.

2. In a motor vehicle having an internal combustion engine, a carburetor therefor having a mixture conduit, a throttle valve in said conduit, variable drive ratio power transmission mechanism, an electro magnet for changing the drive ratio, a control circuit for said electro-magnet including a normally closed switch device, manually operable mechanism for opening said switch, a blocking element movable to a position to block the opening of said switch, and a spring opposed pressure responsive device having a suction connection with said mixture conduit at a point anterior to said throttle valve and being responsive to a predetermined suction therein for moving said blocking element to a blocking position.

3. In a device of the class described, a carburetor having a mixture conduit, a throttle valve in said conduit, an operating lever for said valve, a control switch, an operating connection between said lever and said switch, a blocking element movable to a blocking position between said mechanism and said switch, a spring opposed suction device responsive to a predetermined suction in said mixture conduit for moving said blocking element into a blocking position, said mechanism comprising a spring extendedtelescoping link whereby said throttle is movable when said blocking element is in a blocking position.

4. In a carburetor having a mixture conduit, a throttle valve in said conduit, an operating arm for said throttle valve, control switch structure mounted on said carburetor comprising a slidable switch blade member, and a telescoping plunger for moving said switch blade member, said plunger being constructed and arranged to be moved in a switch opening direction by said throttle operating arm as said throttle valve approaches a full open position, a blocking element movable to a position between said plunger and said switch blade to prevent the shifting thereof and a spring opposed pressure responsive device connected to said mixture conduit at a point anterior to said throttle valve for moving said blocking member into a blocking position.

5. In a carburetor having a mixture conduit, a normally closed control switch comprising a movable switch blade element, a plunger member for moving said switch blade, a perforated blocking member between said switch blade element and said plunger, spring means for normally holding said blocking member in alignment to permit the passage of said plunger therethrough, and a suction device connected to said mixture conduit for` moving said blocking member out of alignment whereby the shifting of said switch blade by said plunger is prevented.

6.A In a device of the class described, a carbureto"r having a mixture conduit, a throttle valve in scid conduit, a control switch, mechanism forming an operating connection between said throttle and said control switch, a blocking element movable to a. position in which the operation o1' said control switch is prevented, and a pressure responsive device having a suction oonnection with said induction conduit at a point anterior to said control valve and being responsive to a predetermined suction therein to move said blocking element into a blocking position to prevent the operation ,of said control switch by the movement of said throttle. v

7. In a device of the class described, a carburetor having a throttle valve, a. manually controlled throttle operating lever, a control switch, mechanism forming an operative connection between said throttle lever and said switch, a blocking element movable to a blocking position between said mechanism and said switch. said mechanism comprising a spring extended telescoping link whereby said throttle may be moved when said blocking element is in a blocking position.

8. In combination, a carburetor having a mixture conduit, a throttle valve in said conduit, a switch device having a movable switch blade element, a throttle lever, a collapsible link between said lever and said switch blade, and a blocking element movable to a. position between said collapsible element and saidswitch blade element,

9. In combination, a carburetor having a mixture conduit, a throttle valve in said conduit, a switch device having a movable switch blade element, mechanism connected to said throttle valve for moving said switch blade element, a collapsible member between said mechanism and said switch blade element, a blocking element movable to a position between said collapsible member and said switch blade element, and a device responsive to suction in said conduit for moving said blocking element.

LEONARD D. BOYCE.

IAN C. MCKECHNIE. 

